Word meld and weld is slightly different from previous puzzles of this nature.
In this puzzle you have to get from the word SISTER to the word BROTHER.
The rules are simple, either change a letter, add a letter or remove a letter.
The only proviso is that each word created must be a genuine English word.

Here are some more to try

BLACK
:
:
WHITE

NIGHT
:
:
DAY

HUNGRY
:
:
THIRSTY

Can you find any other such word meld/welds that go from one word to its opposite?